A Missouri man who was convicted of abducting, raping and killing a Kansas City teenager while she waited for a school bus in 1989 was executed early Wednesday morning.

Michael Taylor was pronounced dead at 12:10 am at the state prison in Bonne Terre, Mo. after being put to death by lethal injection. His attorneys had filed last-minute appeals arguing that the execution drug the state purchased from a compounding pharmacy could cause inhumane pain and suffering. The AP reports that Taylor gave no final statement and showed no obvious signs of distress.

In March 1989, Taylor and another man, Roderick Nunley, abducted 15-year-old Ann Harrison as she waited in her driveway for the school bus. The two men raped Harrison and, fearing she could identify them, stabbed her 10 times with kitchen knives. They left her body in the trunk of a stolen car, which was found the next day. DNA evidence later linked the pair with the crime. Nunley remains on death row with appeals pending.

Taylor’s execution is the fourth in Missouri in as many months. For years, the state used a three-drug combination for executions, but recently switched to lethal injection drug pentobarbital and has relied on largely-unregulated compounding pharmacies to obtain the drugs after pharmaceutical companies refused to sell them to be used in executions.

A few weeks ago, Taylor’s lawyers sued The Apothecary Shoppe, a compounding pharmacy in Tulsa, Okla., which planned to sell pentobarbital to the Missouri Department of Corrections. The pharmacy agreed not to manufacture the drugs for the state, but Missouri obtained the drugs elsewhere and did not disclose their source. Taylor’s lawyers then filed a last-minute appeal, which questioned the use of an unnamed pharmacy to obtain the drug; however, the state’s execution protocol allows for the manufacturer of the drug to remain anonymous.

Harrison’s father and two of her uncles witnessed Taylor’s execution and declined to give a public statement.